diff --git a/src/librustc_front/lowering.rs b/src/librustc_front/lowering.rs index db30ee9a5d2..136c25f425e 100644 --- a/src/librustc_front/lowering.rs +++ b/src/librustc_front/lowering.rs @@ -1502,8 +1502,9 @@ pub fn lower_expr(lctx: &LoweringContext, e: &Expr) -> P<hir::Expr> { hir::MatchSource::ForLoopDesugar, None); - // `{ let result = ...; result }` - let result_ident = lctx.str_to_ident("result"); + // `{ let _result = ...; _result }` + // underscore prevents an unused_variables lint if the head diverges + let result_ident = lctx.str_to_ident("_result"); let let_stmt = stmt_let(lctx, e.span, false, result_ident, match_expr, None); let result = expr_ident(lctx, e.span, result_ident, None); let block = block_all(lctx, e.span, hir_vec![let_stmt], Some(result)); diff --git a/src/test/run-pass/issue-30371.rs b/src/test/run-pass/issue-30371.rs new file mode 100644 index 00000000000..a4ab475e9ea --- /dev/null +++ b/src/test/run-pass/issue-30371.rs @@ -0,0 +1,18 @@ +// Copyright 2012 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +#![deny(unused_variables)] + +fn main() { + for _ in match return () { + () => Some(0), + } {} +} +